经消毒的致倦库蚊在半野外环境下能够向其滋生地自动传播足够剂量的吡丙醚。

Sterilized Anopheles funestus can autodisseminate sufficient pyriproxyfen to the breeding habitat under semi-field settings.

机构信息

Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.

School of Life Science and Bio-Engineering, The Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania.

出版信息

Malar J. 2023 Sep 21;22(1):280. doi: 10.1186/s12936-023-04699-9.

DOI:10.1186/s12936-023-04699-9

PMID:37735680

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10515043/

Abstract

BACKGROUND

Anopheles funestus, the main malaria vector, prefer to oviposit in permanent and/or semi-permanent breeding habitats located far from human dwellings. Difficulties in identifying and accessing these habitats jeopardize the feasibility of conventional larviciding. In this way, a semi-field study was conducted to assess the potential of autodissemination of pyriproxyfen (PPF) by An. funestus for its control.

METHODS

The study was conducted inside a semi-field system (SFS). Therein, two identical separate chambers, the treatment chamber with a PPF-treated clay pot (0.25 g AI), and the control chamber with an untreated clay pot. In both chambers, one artificial breeding habitat made of a plastic basin with one litre of water was provided. Three hundred blood-fed female An. funestus aged 5-9 days were held inside untreated and treated clay pots for 30 min and 48 h before being released for oviposition. The impact of PPF on adult emergence, fecundity, and fertility through autodissemination and sterilization effects were assessed by comparing the treatment with its appropriate control group.

RESULTS

Mean (95% CI) percentage of adult emergence was 15.5% (14.9-16.1%) and 70.3% (69-71%) in the PPF and control chamber for females exposed for 30 min (p < 0.001); and 19% (12-28%) and 95% (88-98%) in the PPF and control chamber for females exposed for 48 h (p < 0.001) respectively. Eggs laid by exposed mosquitoes and their hatch rate were significantly reduced compared to unexposed mosquitoes (p < 0.001). Approximately, 90% of females exposed for 48 h retained abnormal ovarian follicles and only 42% in females exposed for 30 min.

CONCLUSION

The study demonstrated sterilization and adult emergence inhibition via autodissemination of PPF by An. funestus. Also, it offers proof that sterilized An. funestus can transfer PPF to prevent adult emergence at breeding habitats. These findings warrant further assessment of the autodissemination of PPF in controlling wild population of An. funestus, and highlights its potential for complementing long-lasting insecticidal nets.

摘要

背景

致倦库蚊是主要的疟疾传播媒介，它更喜欢在远离人类住所的永久性和/或半永久性滋生地产卵。识别和进入这些滋生地存在困难，这危及了常规幼虫防治的可行性。为此，开展了一项半现场研究，以评估吡丙醚（PPF）通过致倦库蚊自动传播的潜力，从而达到控制目的。

方法

该研究在半现场系统（SFS）内进行。在该系统中，设有两个完全相同的独立隔室，处理隔室中放置了一个涂有 0.25 g AI 的 PPF 处理粘土地板，对照隔室中放置了一个未处理的粘土地板。在两个隔室中，均提供了一个由 1 升水组成的塑料盆制成的人工滋生地。将 300 只饱吸血的 5-9 日龄雌性致倦库蚊分别放置在未处理和处理粘土地板中 30 分钟和 48 小时，然后释放用于产卵。通过比较处理组与适当的对照组，评估了 PPF 通过自动传播和绝育作用对成虫出现、繁殖力和育性的影响。

结果

暴露 30 分钟的雌蚊的成虫出现率分别为 15.5%（14.9-16.1%）和 70.3%（69-71%）（p<0.001），暴露 48 小时的雌蚊的成虫出现率分别为 19%（12-28%）和 95%（88-98%）（p<0.001）。与未暴露的蚊子相比，暴露蚊子所产的卵及其孵化率显著降低（p<0.001）。大约 90%暴露 48 小时的雌蚊保留异常卵巢滤泡，而暴露 30 分钟的雌蚊中只有 42%保留异常卵巢滤泡。